Project description:The B cell antigen receptor (BCR) is a signaling complex that mediates differentiation stage-specific cell fate decisions in B lymphocytes. While several studies have evidenced differences in signal transduction components as being key to contrasting phenotypic outcomes, little is known about the differential BCR-triggered gene transcription. Here we defined transcriptional changes underlying BCR-induced apoptosis and proliferation of immature and mature B cells, respectively. These findings provide the first insights into the early transcriptional events leading to deletion or clonal expansion of B cells upon antigen recognition. Keywords: cell type comparison, development or differentiation design, time course, compound treatment design, microarray experiment record Total RNA was extracted from immature (IM) and mature (M) B cells both freshly isolated (0h) and stimulated with (BCR) or without (ctrl) anti-μ F(ab’)2 for 2, 8 or 24h. Following RNA extraction, one round of mRNA amplification was applied using the MessageAmpTM Kit (Ambion). All samples, including the amplified Universal Mouse Reference RNA (Stratagene) which served as a reference at each hybridization, were reverse-transcribed and indirectly labeled with Cy3 and Cy5 (Amersham). Quality was controlled by performing 6 or 8 hybridizations of each sample to the cDNA arrays using a dye-swap strategy. 94 arrays were used for hybridization in total.
Project description:The B cell antigen receptor (BCR) is a signaling complex that mediates differentiation stage-specific cell fate decisions in B lymphocytes. While several studies have evidenced differences in signal transduction components as being key to contrasting phenotypic outcomes, little is known about the differential BCR-triggered gene transcription. Here we defined transcriptional changes underlying BCR-induced apoptosis and proliferation of immature and mature B cells, respectively. These findings provide the first insights into the early transcriptional events leading to deletion or clonal expansion of B cells upon antigen recognition. Keywords: cell type comparison, development or differentiation design, time course, compound treatment design, microarray experiment record
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:We used single-cell transcriptomics and BCR sequencing to analyze B cell development in 56R and LAPTM5KO 56R mice. We found increased proportions of immature B and mature B cells in LAPTM5KO 56R mice compared to 56R mice. QuSAGE analysis revealed that immature B cells from LAPTM5KO 56R mice were enriched in PI3K-Akt, mTOR, Ras and MAPK signaling pathways that contribute to cell survival. Moreover, mature B cells from LAPTM5KO 56R mice were enriched for activated autoimmune disease and transplant rejection pathways compared with those from 56R mice, suggesting that LAPTM5KO 56R mice might be more susceptible to autoimmunity. Single-cell BCR sequencing showed that LAPTM5 deficiency resulted in less reduction in LC diversity in mature B compared to immature B cells.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.
Project description:Although early developmental processes involve cell fate decisions that define the body axes and establish progenitor cell pools, development does not cease once cells are specified. Instead, most cells undergo specific maturation events where changes in the cell transcriptome ensure that the proper gene products are expressed to carry out unique physiological functions. Pancreatic acinar cells mature post-natally to handle an extensive protein synthetic load, establsih organized apical-basal polarity for zymogen granule trafficking, and assemble gap-junctions to perimt efficient cell-cell communication. Despite significant progress in defining transcriptional networks that control initial acinar cell specification and differentiation decisions, little is know regarding the role of transcription factors in the specification and maintenance of maturation events. One candidate maturation effector is MIST1, a secretory cell-restricted transcription factor that has been implicated in controlling regulated exocytosis events in a number of cell types. Embryonic knock-out of MIST1 generates acinar cells that fail to establish an apical-basal organization, fail to properly localize zymogen granule and fail to communicate intra-cellularly, making the exocrine organ highly suceptible to pancreatic diseases. In an effort to identify the gene expression differences responsible for MIST1 regulating mature acinar properties. We generated a tamoxifen-inducible mouse model where MIST1 expression could be activated in vivoand performed gene expression arrays on wildtype, MIST1-null, and induced MIST1 pancreatic RNA.